The invention relates to a bistable valve for the alternate closing of flexible pipes which in spite of its simple construction can be operated by short pulses and is capable of assuring that at the midpoint of the switching, both of the pipes are closed.
The above-noted advantageous characteristics can be accomplished by an appropriate construction of the closure member and its forced path of movement.
The closure member of the bistable valve according to the invention is provided with a pair of parallel closure edges which, depending from the position of the closure member, exert alternately pressure on the pipes by the fact that the opposite side of the closure member is moved over an appropriately selected arch.
There are known pipe clamps which are operable with the help of various mechanical and electromagnetic means, and in which the power necessary for the operation should be exerted directly against the flexible pipe. A switching valve which operates with such mechanism possesses various disadvantages.
In one aspect, in order to retain the limiting positions, a constant loading of the operating mechanism is necessary, consequently, in the case of electromagnetic operation, there is need for a large coil and for a constant consumption of energy. On the other hand, it is difficult to assure that in the transient position both pipes be closed, which in the use of switching valves is a necessary requirement.